The PSA test s becoming more popular with men over 40 and could save your life. Here we will look at prostrate cancer and the test and how it could help you. What is PSA? PSA is prostate specific antigen. PSA is a protease (protein) secreted the prostate gland. Its levels in the blood are elevated in men with both benign prostatic hyperplasia and prostate cancer. PSA is now an accepted and routine screening test for prostate cancer.